This invention relates to marine seismic exploration and more particularly to a sectionalized marine seismic cable employing articulated connector assemblies between individual cable sections to permit relative bending movement between such individual cable sections.
The older types of seismic cables used in the marine exploration industry were of sturdy construction and short length, on the order of a thousand feet or so. These old cables were towed behind a recording boat at a level in the water where the operators on board the boat could easily watch the cables and notice when the cables were caught on any obstructions in the water. The old cables usually included heavy stress members and rigid connections between sections of the cables so that they were relatively invulnerable to being scraped or torn. If the old cables became hung on an underwater obstruction, the tension in the cable could be felt on board the boat. The operators on the boat could easily stop the boat and disentangle the cable before damage occurred.
In recent years the exploration industry has begun to use cables of more delicate construction and relatively long length, on the order of one or two miles. Most of these new cables are designed to be streamlined in the water and are encased in a thin flexible sheath that is vulnerable to ripping or tearing when the cable is caught on an obstruction in the water. These new cables are usually filled with a fluid, such as kerosene, to make them the same density as the water so that they may ride below the surface of the water.
Sometimes these new, streamlined and delicate cables are towed by the recording boats at depths below the surface, and at other times may be weighted for laying on the ocean bottom. During deployment, recording or retrieval, these cables may become ripped or torn on underwater obstacles such as water buoys, drilling rigs, docks, fishing nets and all sorts of water bottom objects.